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2003 Kia Rio
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Discussion Starter · #1 ·
Bought a 2003 Rio with 62,000 miles on it. Runs great, shifts great, but has a rough idle when you put it in any gear, or in park when you turn the air conditioner on.

The maintenance I have done so far includes: new timing belt, water pump, idler and tensioner; spark plugs and wires; fuel filter; air filter; oil & filter; replaced worn transmission mount.

Idles in park without A/C on just fine - about 700 or 800 rpm - very smooth. With A/C on in park, or in gear, idles about the same rpm (700-800), but is rough.

I've seen on some threads it is recommended to clean the IAC. Never done this, so I would need some instruction.

Thanks!
 

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2002 Kia Rio, 2011 Kia Sorento 2005 f 250 1996 geo metro 1992 f 150
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Search my or kevster's post's on the subject it's easy to do and cheap also, it's one thing to try. Basically pull it off and use carb spray to un stick it if it is stuck. spray it up good and work it back and forth keep spraying as needed till it's free when your done the valve should be slightly open and move freely Fill out your profile some more general location where you live. if you live in the usa you can register at http://www.kiatechinfo.com/ for service materials for free. Good luck with it and good job on changing that timming belt for sure.
 

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Discussion Starter · #4 ·
Still not fixed

I took the IAC valve off and sprayed with carb cleaner. Seemed to move freely with no issues. Also sprayed and cleaned as much of the throttle body as I could.

When I got it all back together and started it up, everything was MUCH better. Thought I had it fixed. Noticed that the RPM's were in the 800-900 range. Stayed in that range regardless if A/C was on, whether or not it was in gear, or just in park. Running very smooth.

However, as the car started to warm up, and after I got on the throttle a few times, the car settled into to a lower RPM range and the problem returned. It settled into that 700-750 range, and I was right back to where I started.

My owners manual says that at 60,000 miles (which I am just over) the idle speed adjustment should be inspected. Is that the IAC valve the manual is referring to? Is it referring to something else?

Any and all help or feedback would be appreciated. Thanks!
 

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>> My owners manual says that at 60,000 miles (which I am just over) the idle speed adjustment should be inspected. Is that the IAC valve the manual is referring to? Is it referring to something else? <<

It's the same item, called IAC on some models, ISC on others.. Same part.
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Read your post w/ interest above, (nice job on the TB belt BTW.) - some other items you may want to consider as part of routine maintenance:

Fuel filter, (x) done
PCV Valve,
* Vacuum hose inspection ..
Air filter, (x) done


Cleaning the MAF sensor with (CRC-brand) MAF cleaner - to clean the MAF sensor, carefully remove from the intake tube, and spray the inside sensor vanes with the cleaner.. You should -not- touch the sensor vanes at all, they are very delicate and may break! After spraying w/ cleaner and letting completely dry, -repeat-, when dry, reinstall on the vehicle. *Handle the MAF sensor like any other piece of delicate electronics you own..*

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When I had idling issues w/ the '97 Ford Aspire (aka: rebadged Kia Avella) here recently, I hooked up a vacuum gauge, and saw that the needle was not steady at idle (had some jitter) and a little low, so I checked all vacuum hoses, found a few that were loose on their respective parts.. after clipping a little bit (1/4" - 1/2") of old vacuum hose off the end and refitting, problem was solved.

In my case, the hose connections to the EGR valve and Fuel Pressure Regulator (FPR) were loose enough to let in illegal air, causing the low/uneven idle condition.. *Not saying this is the issue on -your- vehicle, but hope the info helps.

This may sound simplistic, but having clean air, clean fuel, tight connections (vacuum hoses, intake tubes <-> air filter to throttle body) really does help in regards to good idling of our vehicles..

If after making sure the intake tube connections are good and tight, that vacuum hoses are in good condition and secure on all components / ports on the Intake manifold, and clean air and fuel are being delivered, if you are still having issues, post back, we'll try to help,

Regards,
GottaCruise
 

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2003 Kia Rio
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Discussion Starter · #6 ·
Thanks GottaCruise, that's great info!

I was preparing to get back into it this weekend. I bought a pcv valve, and I have ordered an IAC valve. Decided that regardless, I wanted to go ahead and just change it out and completely eliminate that from the equation.

Lo and behold, I finally got the check engine light to come on. Going to AutoZone after work tomorrow to have them pull the code(s). Really looking forward to what it shows.
 

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Discussion Starter · #7 ·
Good grief!

I think I am the victim of a bad throttle position sensor job.

Went to Auto Zone and they pulled 2 codes. One was the IAC and the other was the TPS. They had the TPS in stock, so I brought one home.

After removing everything to expose the TPS, I quickly realized that you have to take the throttle body off in order to get to the two screws that mount the TPS. That's when I discovered that the throttle body only had a couple of broken pieces of gasket left from a previous removal. Also found that the rubber sleeve that connects the top of the throttle body to the MAF sensor housing had a corner pushed down and folded over under the clamp that holds it in place. The TPS that I removed was an exact duplicate of the one that I bought at Auto Zone. Almost 99% sure it is not the original equipment.

I really think that someone before me got a check engine light, went to the parts store to have them diagnose it, bought a TPS, and then did a butcher job trying to put it on and back together!

I didn't know that I was going to be removing the throttle body, so I won't have a gasket until tomorrow. Going to get a new sleeve as well. I think they call it an Air Mass Meter Boot. Did replace the pcv valve while I was at it. The old one sounded "klunky", so I think it definitely needed to be replaced.

If air leaks can cause this problem, I definitely found some today. Still waiting on the IAC that I ordered on-line. I'm actually encouraged by all this. I've found a lot of problems that needed fixed. Hopefully she will run like a top after everything is back together.
 

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Wow - Good Grief indeed. :)

Nicely done on finding those issues - that TB gasket alone would affect idle, not to mention the MAF tube.. ( Sounds almost exactly like the issues I started finding when I was rehabbing the Aspire, I think the previous owner used a hatchet as a screwdriver to tighten the air intake system.. :eek: )

I'm hopeful that your hard work will payoff in getting the issue resolved.

Please keep us posted on your progress,

Regards,
GottaCruise
 

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Discussion Starter · #9 ·
Doing better

Replaced the pcv valve, throttle position sensor, throttle body gasket, and MAF boot.

IAC valve broke when I was putting it on! :mad:
I really thought I was being careful not to torque the screws to tight, but the plastic housing broke apart where the screw holes are and I had no choice at that moment but to put the old / carb cleaned one back on.

When I put everything back together and started it up, it wasn't good. Rough and even misfired some. Previously, in order to try and get a higher idle speed, I had experimented with adjusting the throttle stop screw on the throttle body. BAD MOVE! DON'T DO THIS! After trying to readjust in both directions with no luck, I finally backed that stop screw way back out until, to my great relief, the engine smoothed out! Tightened up the set screw and thanked the Man upstairs.

The car is idling much better right now. The rpms stay pretty steady right around 750. Put it in gear and the rpms dip for a second, but go right back to 750. Turn on the A/C, same thing. Seems pretty smooth with one exception, and that involves the A/C.

When I turn the compressor on, the car idles fine, but I feel a vibration. It's enough of a vibration that the exhaust pipe between the cat converter and the muffler vibrates to the point that it rattles and buzzes. Don't notice the compressor vibrating or making noise, just seems like the load creates vibration and the resulting noise that seems to come from exhaust locations, manifold on down. I haven't checked the mounting hardware or bolts yet to see if anything is loose, but that was next on my list.

Only other issue is cold starting. The temperature dropped into the 40's overnight a couple of times, and first thing in the morning it took 2 or 3 attempts to get it started. Afterwards, it ran fine, and started fine the rest of the day. Just that initial cold start was a problem.

I appreciate all the help and advice. Any ideas on my remaining issues would be very welcome!
 

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Hi lpickle,

That's lousy about the replacement IAC valve breaking. Dunno how bad it's cracked, but maybe some 5 minute plastic epoxy resin may mend it back up..

re: vibration/noise w/ A/C compressor on: I would be checking the alignment of the exhaust system to make sure it is centered between any heat shields from the front -> back, and would 'coax' any piping close to or resting on a heat shield back to center, and checking all rubber hangers, to see if any are shifted or worn.

If no joy there, I'd take a closer look at the engine motor mounts: if the trans mount was bad, it's possible the motor mounts are also worn -> transmitting engine vibration to the body & cabin..

re: hard starting when cold: could still be the (original) IAC causing grief, or could be something else:

I noticed there is a TSB up on the kiatechinfo website regarding cold start for the Rio Cinco - it may be worth checking out on kiatechinfo.com and/or a call to the dealer to see if your vehicle / ECM is one that is affected by the TSB, which involves a ROM flash update to the ECM..

The other thing you might try is to 'tweak' the throttle stop screw back close to original position: with slack in the throttle cable, going a 1/8 turn clockwise per check, without any accessories on / warmed up, then loading w/ accessories (headlamps, A/C, in gear), to see if you can smooth out the idle any further.. Then checking w/ accessories back off.. Then removing any slack in the throttle cable / tightening just before the point of affecting idle, cable should almost be taught, but not affecting idle. (Based on what you wrote, it's most likely very close.)

That's about all I can think of for now - glad to hear you are making progress on the issue..

Regards,
GottaCruise
 
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